.TH mblen 3 "" "" ""
.SH SYNOPSIS
mblen \- minimal multibyte length function
.SH ANSI_SYNOPSIS
#include <stdlib.h>
.br
int mblen(const char *
.IR s ,
size_t 
.IR n );
.br
.SH TRAD_SYNOPSIS
#include <stdlib.h>
.br
int mblen(
.IR s ,
.IR n )
.br
const char *
.IR s ;
.br
size_t 
.IR n ;
.br
.SH DESCRIPTION
When MB_CAPABLE is not defined, this is a minimal ANSI-conforming 
implementation of 
.BR mblen .
In this case, the
only ``multi-byte character sequences'' recognized are single bytes,
and thus 
.BR 1 
is returned unless 
.IR s 
is the null pointer or
has a length of 0 or is the empty string.

When MB_CAPABLE is defined, this routine calls 
.BR _mbtowc_r 
to perform
the conversion, passing a state variable to allow state dependent
decoding. The result is based on the locale setting which may
be restricted to a defined set of locales.
.SH RETURNS
This implementation of 
.BR mblen 
returns 
.BR 0 
if
.IR s 
is 
.BR NULL 
or the empty string; it returns 
.BR 1 
if not MB_CAPABLE or
the character is a single-byte character; it returns 
.BR -1 
if the multi-byte character is invalid; otherwise it returns
the number of bytes in the multibyte character.
.SH PORTABILITY
.BR mblen 
is required in the ANSI C standard. However, the precise
effects vary with the locale.

.BR mblen 
requires no supporting OS subroutines.
.SH SOURCE
src/newlib/libc/stdlib/mblen.c
